Stmicroelectronics S.a.

Stmicroelectronics (rousset) Sas

Christophe Moreaux

Ahmed Kari

Pierre Rizzo

David Naura

Gilles Bas

Olivier Tardieu

Gary Seigneuret

Bruno Leconte

Claude Anguille

Pierre Résidence Port Royal Rizzo

An electromagnetic transponder includes an antenna circuit, a load, and a charge pump transistor having a current path coupled between the antenna circuit and the load. During operation, a retromodulated signal is transmitted at a first level by biasing the charge pump transistor during a first time period such that an impedance of the antenna circuit has a first impedance value and current flows from the antenna circuit to the load. A retromodulated signal at a second level is transmitted by biasing the charge pump transistor during a second time period such that the impedance of the antenna circuit has a second impedance value different than the first impedance value and current flows from the antenna circuit to the load. The retromodulated signals are transmitted at the first and second levels in a sequence determined to transmit information from the electromagnetic transponder.

Method for modulating the impedance of an antenna circuit

An electromagnetic transponder includes an antenna circuit capable of providing signals to a charge pump. The pump includes a first transistor connected to a first capacitor. The transponder also includes means for applying a voltage alternating between first and second values between the gate and the conduction terminal on the side of the first capacitor of the first transistor.

Method for modulating the impedance of an antenna circuit while receiving wireless power

A passive contactless integrated circuit includes an electrically programmable non-volatile data memory (MEM), a charge accumulation booster circuit for supplying a high voltage necessary for writing data in the memory. The integrated circuit includes a volatile memory point for memorizing an indicator flag, and circuitry for modifying the value of the indicator flag when the high voltage reaches a critical threshold for the first time after activating the booster circuit.

Passive contactless integrated circuit comprising a flag for monitoring an erase/programming voltage

A method for configuring a memory space, the method including reading a piece of configuration information in the memory space, determining a division of at least one part of the memory space into memory banks according to the configuration information read; and allocating to each of the memory banks an access number to be used to access a data location in the memory bank, in combination with a logic address of the location in the memory bank.

Method for configuring a memory space divided into memory banks

An electromagnetic transponder and a method for controlling by pulse trains a switch for modulating the load of this transponder in an electromagnetic field from which it extracts its power supply, the duty ratio of the pulses being controlled according to the transponder supply voltage.

Transponder load modulation

A method of reading a group of memory words from an integrated circuit memory of a contactless tag, comprising the sending by a remote interrogation unit to the contactless tag of a specific command for reading the group of memory words from a given start address, the initialization of an address counter for the contactless tag to the value of the given start address, and the sending by the contactless tag of the memory word at the start address, as well as an iterative process comprising in succession a first step of sending by the remote interrogation unit to the contactless tag of an incrementation marker recognizable by the contactless tag, a second step of incrementation of the address counter for the contactless tag in response to the incrementation marker, and a third step of sending by the contactless tag to the remote interrogation unit of a data frame comprising the memory word stored in the memory at the address pointed at by the current value of the address counter.

Method of reading the memory plane of a contactless tag

A method for modulating the impedance of an antenna circuit supplying pump signals to a charge pump comprising at least one first pump stage and one last pump stage, the last pump stage supplying a continuous voltage. The output of the first pump stage is short-circuited by means of a switch and the last pump stage goes on pumping electric charges and supplying the continuous voltage. Application in particular to RFID passive transponders.

Antenna impedance modulation method

A method is provided for block writing in an electrically programmable non-volatile memory, in which a block to be written in the memory includes at least one word. The method includes determining a word write time by dividing a fixed block write time by the number of words in the block to be written, and controlling the memory to successively write each word in the memory during the write time.

Method for block writing in a memory

A method divides a number Nby a number which can be written in the form 2/k, n and k being whole numbers, and obtains a result N. The result Nis calculated by adding terms N*Ki/2for i ranging from 0 to N, the terms Ki being the constituent bits K, K, K, . . . Kof the number k expressed in binary. The method can be applied particularly to the production of a calibration circuit for calibrating a clock signal in a UHF transponder.

Method for dividing a number by a fraction having a number in the form of a power of 2 at the numerator

A persistent volatile memory cell memorizes a binary datum during a retention time independent from a supply voltage of the memory cell. The memory cell comprises a capacitive memory point supplying a persistent voltage and having a determined discharge time, a switch for triggering the discharge of the memory point when an erase signal has an active value, a switch for triggering the charge of the memory point when a write signal has an active value, and a sense-amplifier circuit having an input receiving the persistent voltage, and an output supplying the binary datum. The memory cell can be applied to the management of an inventory flag in a contactless integrated circuit.

Persistent volatile memory with sense amplifier and discharge switch

A method and device for generating a clock signal, the method including measuring, using a first clock signal, a characteristic of a reference event in a received signal, determining, using the first clock signal, a variation of a characteristic of a second event in a received signal, correcting the measurement according to the variation of the characteristic of the second event, and generating a second clock signal using the first clock signal according to the corrected measurement.

Method and device for generating a clock signal

A binary frequency divider includes a counter paced by an input signal, means for comparing a counting value with first and second threshold values and supplying first and second control signals synchronized with variation edges of a first type of the input signal. The divider includes means for supplying at least one third control signal shifted by a half-period of the input signal in relation to one of the first or second control signals, and control means for generating the output signal using control signals chosen according to the value of at least one least significant bit of the division setpoint. Application is mainly but not exclusively to UHF transponders.

Binary frequency divider

A method and a system for authenticating an electronic tag by a host communicating with this tag via a reader, including: calculating, on the tag side, a first digital signature using at least one first function shared by the tag and the reader, taking into account at least one first secret key known by the electronic tag and the reader only; transmitting the first signature to the reader; calculating, on the reader side, a second digital signal using at least one second function, different from the first function and shared by the reader and the host, taking the first signature into account; transmitting the second signature to the host; and checking, on the host side, the coherence between the second signature and a validation value calculated based on said second function and on a second secret key known by the host and by a single element selected from among the tag and the reader.

Authentication of an electronic tag

A method checks the state of a set of memory cells of a memory having memory cells arranged in a memory array, row and column decoders for selecting a memory cell, and a sense amplifier for supplying a state of the selected memory cell depending on whether the selected memory cell is conductive or non-conductive. The method includes features wherein all the memory cells of a set grouping together several memory cells are selected, and then simultaneously coupled to the sense amplifier, and the sense amplifier supplies a global state of all the selected memory cells to which it is coupled, if the latter are simultaneously non-conductive. Application is provided to the checking of a command for block-erasing a memory.

Method for checking block erasing of a memory and circuit thereof

A method for executing a write command for writing a binary word in a programmable memory, comprises writing each of the bits in a programmed state of a binary word to be written in a corresponding memory cell of the memory, reading each bit of the word written in the memory corresponding to a bit in the programmed state of the word to be written, comparing each bit in the programmed state of the word to be written with a corresponding bit read in the memory, and generating an error signal if at least one bit of the word to be written in the programmed state is different from the corresponding bit read. Application of the method can be particularly but not exclusively to integrated circuits for chip cards.

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Simiane, France

Christophe Moreaux